Open-end spinning of yarn is becoming increasingly commercially popular because of a number of inherent advantages of open-end spinning over conventional ring spinning. Some of the advantages of open-end spinning over ring spinning are: yarn formation and winding are not interdependent, allowing for removal of full packages while the machine is running; package size is theoretically unlimited; power consumption increases little with package weight; and package shape is suitable for most of the succeeding operations so that rewinding is eliminated. Additional advantages are the appearance, processability, and economy of the open-end yarns, and generally improved performance of end-products made with open-end yarns.
While it is desirable to be able to produce open-end novelty yarns (particularly open-end slub yarns), there have been a large number of practical problems associated with conventional techniques and proposals for making open-end novelty yarns. As a result, most novelty (particulary slub) yarns now produced are ring spun. Present conventional and proposed methods for formation of slubbed open-end yarns include applying the slubs to the sliver before it is fed to the spinner; rapidly increasing or decreasing the feeding rate of the sliver; varying the withdrawal speed of the yarn from the spinner (U.S. Pat. 4,144,730); introducing and withdrawing a plurality of needle free ends into the fiber flow pivotal about an axis skew to the fiber flow to cause collection and release (German OFF. No. 26 57 096); and forming the slubs exteriorly of the open-end spinning operation and then adding the slubs in a separate path to a point just before the yarn spinning device.
According to the method and apparatus of the present invention it is possible to produce novelty yarns (particularly slub yarns) having most of the desirable features of conventional ringspun slub yarns. The method is subject to wide applicability and ready control to produce a wide variety of different novelty effects, and the apparatus according to the present invention is basically simple and is believed to be adaptable for use on almost any type of conventional open-end spinning equipment, and in fact can be retrofit onto most conventional open-end spinning equipment.
The invention is useful for making a wide variety of novelty yarns, which in general includes any yarn having unusual or special effects such as nubs, neps, lumps, slubs, or the like. However, the invention is primarily suitable to the production of slub yarns. Slub yarns are a particular species of novelty yarn with soft, thick, unevenly twisted lengths which alternate with essentially normalsized places in the yarn. Slub yarns provide a very definite and readily discernible texture effect in the products into which they are made, the degree of course being dependent upon the frequency and size of the slubs, providing well defined, relatively large surface manifestations in the products produced with the yarn.
According to one aspect of the present invention, open-end spinning of a novelty yarn utilizing an open-end spinning apparatus having a fiber separating device, a twisting device, an elongated thin member, and a fiber transport section interconnecting the separating and twisting devices, is provided by: Effecting controlled formation of effects in the fiber transport section by effecting controlled introduction of the elongated member into the fiber flow within the transport section so that it makes an angle of less than about 45.degree. (about 25.degree.-45.degree.) with respect to the direction of fiber flow; and intermittently passing those effects to the twisting device. Pseudo-random control means are provided for pseudo-randomly controlling insertion and withdrawal of the elongated member into the fiber flow. A twisting device twists the fibers fed thereto, including any effects passed thereto, into a continuous strand of novelty yarn, and the novelty yarn continuous strand is taken up.
According to another aspect of the present invention apparatus for spinning novelty yarn includes means for effecting controlled formation of effects in the transport section of an open-end spinning device, and for occasionally passing the formed effects to a twisting device. The means for effecting controlled formation include: An elongated member having a length long enough to extend from one side of the tubular wall of the fiber transport section to another portion of the tubular member wall. Means for pivotally mounting, for pivotal movement about an axis, the elongated member at a first side of the tubular member wall so that the elongated member has a free end extending angularly from the first side of the tubular member wall generally in the predetermined direction of fiber flow, and so that it is moveable from a collecting position wherein the free end thereof engages, or substantially engages, another side of the tubular member wall to collect effects between the free end and the wall, to a release position wherein the free end is spaced from the tubular member wall. The mounting means may be a pendulum type mounting means, i.e. the axis of pivotal movement is perpendicular to the predetermined direction of fiber flow, and means for oscillating the elongated member about its axis of pivotal movement may provide movement from a first collecting position in engagement, or substantial engagement, with one portion of the tubular member wall, through a release position, to a second collecting position in engagement, or substantial engagement, with another portion of the tubular member wall. Alternatively the axis of rotation and the predetermined direction of fiber flow may be skew. The elongated member may be curved outwardly from the first side of the tubular member wall, or may be straight.
It is the primary object of the present invention to provide a simple and practical method and apparatus for producing open-end novelty (and particularly slub) yarns. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.